Almost half way up the neck it's actually just below half. When I first bought it the thing would overflow like crazy. I went online and saw that bubble magus recomended a minimum of 9in on the water level. I tried that and it still went nuts no matter where I set it to. After a few weeks the bubbles went down way down so I talked to my lfs
whom I purchased it from he told me to set my level to where I can see the bubbles forming at the water line in my sump and to set the water line in my sump at half which puts the level around 6 or 7 inches. He showed me the same exact skimmer that he uses in all his sumps in a working sump the level of the water was lower that what I have now yet his skimmer was working great. Mine now produces bubbles but not quite as high as I As it should. That's not my concern I think it just needs more to skim out. I'm just worried there may be another issue it was almost as if the pump was seized up.
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